1. Field of the Invention
The present invention relates to an apparatus and method for assisting image diagnosis using a three-dimensional medical image representing a chest region of a subject. The invention also relates to a computer readable recording medium on which is recorded a program for the same.
2. Description of the Related Art
A technology for assisting pulmonary image diagnosis using a three-dimensional medical image representing a chest region is known.
For example, a method in which segmentation of pulmonary parechymal tissue is performed on a CT image representing both lungs, then a perfusion map of the segmented image is generated, and an abnormally underperfused area is rendered and displayed comparatively opaque is proposed as described, for example, in U.S. Pat. No. 7,715,608.
Another method in which lung areas are extracted from CT images representing a lung in insipiratory phase and in expiratory phase, a position alignment is performed on the extracted lung areas using a non-rigid registration method to obtain a displacement vector field in the lung area, then a regional lung volume is calculated by calculating exhalation at each point of the displacement vector field, and a state of lung ventilation distribution is visualized in an axial cross-section image or volume rendering image representing the lung based on the regional lung volume is proposed as described, for example, in Japanese Unexamined Patent Publication No. 2005-028121.
Gas exchange occurs with capillary vessel blood in an alveolus of a lung. At that time, carbon dioxide discharged from the blood is conveyed to the outside through a bronchus and oxygen conveyed from the outside through the bronchus is passed to the blood. It is, therefore, advantageous in image diagnosis of lung to interpret an evaluation value representing a perfusion or a regional lung volume in each section of a lung by considering the association with a bronchus or a blood vessel.
But, a bronchus or a blood vessel is complexly distributed over the entire lung field by repeating branching and thinning, and it is extremely difficult to interpret an evaluation value representing a perfusion or a regional lung volume in each section of a lung by considering the association with a bronchus or a blood vessel in an image representing the entirety of a lung as in the method described in each patent document above.
The present invention has been developed in view of the circumstances described above and it is an object of the present invention to provide a medical image diagnosis assisting apparatus and method that uses a three-dimensional medical image representing a chest region of a subject and allows highly accurate pulmonary image diagnosis by considering the association with a branch structure, such as a bronchus or a blood vessel. It is a further object of the present invention to provide a computer readable recording medium on which is recorded a medical image diagnosis assisting program of the present invention.